NEW YORK (Reuters) - Oil prices fell on Monday as news of another weekly increase in U.S. drilling activity had oil forecasters concerned that production cuts from other producing nations may not reduce the global supply glut as much as had been hoped.

The Organization of the Petroleum Exporting Countries and other producers including Russia agreed to cut output by almost 1.8 million barrels per day (bpd) in the first half of 2017 to relieve a two-year supply overhang.

First indications of compliance to that deal show members have cut production by 900,000 barrels per day (bpd) in January, according to Petro-Logistics, which tracks OPEC supply. Reuters' most recent survey indicated that OPEC production declined slightly in December.

The data from Petro-Logistics suggests only 75 percent of the targeted cuts would be met, said Tony Headrick, energy analyst at CHS in Minnesota.

"There's an apprehension about how big that cutback is going to be versus the strength in U.S. crude production," Headrick said. "That gap is a little narrower than folks had anticipated more recently."

As a result, oil may have enough support to stay just above $50 a barrel but not get much higher than that, said Carl Larry, director of business development for oil and gas at Frost & Sullivan.

The cuts have encouraged drillers in low-cost U.S. shale producing regions to ramp up activity, which will temper any price gains, Larry said.

The oil market also declined as downward pressure weighed on global markets facing uncertainty after sweeping U.S. regulatory changes.

"As we see weakness in the equities, it's carrying over into other sectors like energy and even the grain markets," said Phillip Streible, senior market strategist at RJO Futures in Chicago. "The dollar index was also quite strong all day, which also weighs on prices."

Analysts at J.P. Morgan said they saw a rise in oil prices beyond $60 a barrel in 2018 as unlikely.

"For prices to be supported above $60/bbl in 2018 would likely require continued OPEC output reductions that continue to tighten the market beyond Q3 '17 – something that looks unlikely at this juncture," they said in a report to clients.

(Additional reporting by Aaron Sheldrick and Osamu Tsukimori in Tokyo and Karolin Schaps in London; Editing by David Gregorio and Paul Simao)